Chemicals, plastics and rubber industries

Magnesium parameters for the semiempirical AM1 method developed using a genetic algorithm

Article Abstract:

Magnesium parameters to be applied in a semiempirical AM1 technique were obtained through a specially designed genetic algorithm. Prioritization priorities included development of a robust parametrization which can describe a broad range of characteristics in varied chemical environments. Specifically, the test data set included a selection of the heats of formation, geometric characteristics, dipole moment and ionization energies, examined for 32 compounds including halides, oxides, hypervalent compounds, organometallics and porphyrins.

A combined quantum mechanical/molecular mechanical study of the structure of the cofactors in the reaction centers of purple bacteria

Article Abstract:

A computational investigation of the bacterial photosynthetic reaction center was done by optimizing the structure of Rhodobacter sphaeroides and Rhodopseudomonas viridis' cofactors localized in their reaction centers. Results indicate that the distortions in the geometries of the cofactor are regulated by the protein-cofactor interactions. In addition, it was also observed that the cofactors in the L-side fit more snugly together within the protein environment as compared to their M-side counterparts.

Stark and absorption spectra for the hole-transfer band of the bactreiochlorophyll special pair in the wild type and mutants of the bacterial reaction center of Rhodobacter sphaeroides are presented, along with extensive analyses based on nonadiabatic spectral simulations. Dramatic changes in the Stark spectra are induced by the mutations, which are readily interpreted in terms of the redox-energy asymmetry and degree of charge localization in the special-pair radical cation.